Church Slavonic

Church Slavonic is a Slavic language, that is used, both historically and in modern times, as a liturgical language by various Eastern Christian denominations. During medieval and early modern periods, it was also used as a literary language among Slavs. It stemmed from the Old Church Slavonic (9th-10th centuries), and later developed by adopting various regional and dialectal influences from local Slavic vernaculars, thus branching into several varieties, also called recensions, or redactions.

In its conservative form, that was standardized in the 18th century, it is used today by Eastern Orthodox churches in Belarus, Bosnia and Herzegovina, Bulgaria, Czechia and Slovakia, Croatia, North Macedonia, Montenegro, Poland, Russia, Serbia, Slovenia, and Ukraine. The language also appears in the services of the Russian Orthodox Church Outside of Russia, the American Carpatho-Russian Orthodox Diocese, and occasionally in the services of the Orthodox Church in America.

In addition, Church Slavonic is used by some churches which consider themselves Orthodox but are not in communion with the Orthodox Church, such as the Montenegrin Orthodox Church and the Russian True Orthodox Church. The Russian Old Believers and the Co-Believers also use Church Slavonic.

Church Slavonic is also used by Greek Catholic Churches in Slavic countries, for example the Croatian, Slovak and Ruthenian Greek Catholics, as well as by the Roman Catholic Church (Croatian and Czech recensions).

In the past, Church Slavonic was also used by the Orthodox Churches in the Romanian lands until the late 17th and early 18th centuries, as well as by Roman Catholic Croats in the Early Middle Ages.

The language is also used in some communities belonging to the Orthodox Church of Finland.